1. Field of the Invention
The present invention relates to a plastic molding having an anisotropic, stereoscopically deep luster and a method of molding the same,
2. Description of the Prior Art
In order to impart a special luster to a plastic molding such as a container, a method has hitherto been used wherein a pearlescent pigment containing mica or the like is added to a thermoplastic resin, and a plastic molding having a pearlescent luster has been produced by melt-molding the thermoplastic resin containing a pearlescent pigment added thereto.
In the above method wherein a pearlescent pigment is added, however, changes in the particle diameter and the amount of addition of the pearlescent pigment are substantially the sole means for developing various types of luster. In this method, no molding having an excellent appearance rich in a variation can be produced, and the development of a plastic molding, such as a container, having a better appearance rich in a variation has been desired in the art from the viewpoint of decoration. Further, since the above pearlescent pigment is expensive, the cost is disadvantageously high.
For this reason, a proposal has been made on a method of imparting a special luster to a plastic molding through the utilization of a resin composition comprising resins incompatible with each other. For example, Japanese Patent Publication No. 39336/1986 discloses a resin container produced by molding a resin composition comprising 10 to 99% by weight of a polyester resin and 1 to 90% by weight of a polyolefin resin. In this case, the thin-walled part of the container is unidirectionally oriented and has metallic luster. Further, Japanese Patent Publication No. 24253/1986 discloses a cosmetic bottle made of a plastic having a flow pattern like that of a nimbostratus produced by subjecting a resin mixture comprising 99.5 to 90% by weight of a polyester resin and 0.5 to 10% by weight of a metacrylic resin to stretch blow molding.
Although a plastic molding which has been molded by a conventional method by making use of a resin composition comprising resins incompatible with each other has a beautiful appearance, it has only a metallic luster which is disagreeable for man, which renders it unsuitable as a container for cosmetics or the like required to have a high-gradeness. Further, the above molding has a problem that it has no luster superior to the plastic molding containing a pearlescent pigment. Further, it is difficult to make the above plastic molding having a combination of excellent luster and high impact strength.